Systems and methods for augmented reality devices with light security

ABSTRACT

Apparatus and method of reducing light leakage from display devices are described. An embodiment of reducing light leakage from display devices includes providing an optical shutter that is configured to block light from a display device from being emitted into the ambient environment when the display device is in a bright state and configured to display visual information to the user. The optical shutter can be configured to transmit light from the ambient environment to the user when the display device is not displaying visual information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/146,789, filed on May 4, 2016, which claims the benefit of priorityunder 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No.62/157,254, filed on May 5, 2015 and titled “AUGMENTED REALITY HMDPROVIDING INCREASED LIGHT SECURITY;” and of U.S. Provisional PatentApplication No. 62/221,985, filed on Sep. 22, 2015 and titled “AUGMENTEDREALITY HMD PROVIDING INCREASED LIGHT SECURITY.” Each of theabove-identified applications is hereby incorporated by reference hereinin its entirety for all purposes.

BACKGROUND Field

This disclosure relates to methods and systems for providing displayswith increased light security such that light from the displays isviewed by users viewing the displays and leakage of light from thedisplays into the ambient environment is reduced.

Description of the Related Technology

Advances in display technologies and mobile computing systems havefacilitated the development of augmented reality (AR) systems that canpresent a user with a view of the real physical world that surrounds theuser augmented with computer-generated information such as text, data,graphics, images, video, etc. Example of such information may include,maps, GPS data, photos. This supplemental content may be presented in amanner wherein the user perceives the computer generated information tobe superimposed on or adjacent to the view of the real-world objects infront and/or surrounding the user. Presentation of this additionalcontent can be provided in real-time.

SUMMARY

An innovative aspect of the subject matter disclosed herein isimplemented in an optical system comprising a display device; a beamcombiner; and a shutter. The display device has a first bright displaystate when the display device emits light and a second dark displaystate when the display device emits a reduced amount of light. Theshutter has a first blocking shutter state in which the shutter blockslight passing through the beam combiner and incident on the shutter anda second transmissive shutter state in which the shutter transmits lightso that light can pass through the beam combiner. The shutter isconfigured to be controlled by a control system, such that the shutteris in the first blocking shutter state when the display device emitslight and the shutter is in the second transmissive shutter state whenthe amount of light emitted from the display device is reduced.

In various embodiments of the optical system, the display device cancomprise a transmissive display, a reflective display or an emissivedisplay. In various embodiments of the optical system, the displaydevice can include a source of front illumination for illuminating areflective display. The beam combiner can be configured to redirectlight emitted from the display device towards a viewer disposed to viewa scene through the optical system. The beam combiner can be configuredto transmit ambient light from the scene incident on the optical systemthrough the shutter to the viewer. The control system can be configuredto control the shutter by providing an electrical signal having avoltage level V_(blocking) that causes the shutter to be in the firstblocking shutter state and a voltage level V_(transmit) that causes theshutter to be in the second transmissive shutter state. A duration oftime when the electrical signal has the voltage level V_(transmit) canbe greater than a duration of time when the electrical signal has thevoltage level V_(blocking). The control system can be configured tosynchronize transitioning the shutter between the first blocking shutterstate and the second transmissive shutter state with transitioning thedisplay device between the first bright display state and the seconddark display state. The control system can be configured to transitionthe shutter between the first blocking shutter state and the secondtransmissive shutter state at a rate faster than the unaided human eyecan detect. The control system can be configured to transition theshutter between the first blocking shutter state and the secondtransmissive shutter state at a rate between about 1 microsecond andabout 100 milliseconds. Various embodiments of the optical system can beincluded in a head mounted display, a tank sight and/or a gun sight.

The shutter can be substantially opaque such that ambient light is nottransmitted through the shutter in the first blocking shutter state. Theshutter can be substantially transmissive such that ambient light istransmitted through the shutter in the second transmissive shutterstate. The shutter can be configured to block greater than 50% of thelight emitted from or reflected by the display that passes through thebeam combiner or is incident on the shutter in the first blocking state.In various embodiments, the shutter can be configured to block greaterthan 40%, greater than 60%, greater than 70%, greater than 80% orgreater than 90% of the light emitted from or reflected by the displaythat passes through the beam combiner or is incident on the shutter inthe first blocking state.

In the first blocking state, the shutter can be configured to block lessthan 100%, less than 98%, or less than 95% of the light emitted from orreflected by the display that passes through the beam combiner or isincident on the shutter. In various embodiments of the optical system,the beam combiner can comprise a waveguide. In various embodiments ofthe optical system, the shutter can comprise an opto-mechanical or anelectro-optic device.

An innovative aspect of the subject matter disclosed herein isimplemented in a method of reducing light leakage from a display devicehaving a first bright display state when the display device emits lightand a second dark display state when the display device emits a reducedamount of light. The method comprises providing a shutter having a firstblocking shutter state in which the shutter has a reduced transmissivitywhen the display device is in the first bright display state and lightfrom the display device is incident on the shutter and a secondtransmissive shutter state in which the shutter has an increasedtransmissivity when the display device is in the second dark displaystate.

Various embodiments of the method can further comprise providing anelectrical signal having a voltage level V_(blocking) that causes theshutter to be in the first blocking shutter state and a voltage levelV_(transmit) that causes the shutter to be in the second transmissiveshutter state. Various embodiments of the method can further comprisesynchronizing transitioning the shutter between the first blockingshutter state and the second transmissive shutter state withtransitioning the display device between the first bright display stateand the second dark display state. The shutter can be transitionedbetween the first blocking shutter state and the second transmissiveshutter state at a rate faster than the unaided human eye can detect.The shutter can be transitioned between the first blocking shutter stateand the second transmissive shutter state at a rate between about 1microsecond and about 100 milliseconds.

Details of one or more implementations of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages will becomeapparent from the description, the drawings, and the claims. Neitherthis summary nor the following detailed description purports to defineor limit the scope of the inventive subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

Example implementations disclosed herein are illustrated in theaccompanying schematic drawings, which are for illustrative purposesonly.

FIG. 1 is a schematic diagram of an augmented reality (AR) head mounteddisplay (HMD) device that includes a display device and a beam combiner.

FIG. 2 schematically illustrates an embodiment of an AR-HMD deviceincluding a shutter that reduces leakage of light from the displaydevice.

FIG. 3A illustrates the variation of an electrical control signal thatcan switch the shutter between a blocking state and a transmit statethereby varying the transmissivity of the AR system between a firsttransmittance and a second transmittance.

FIG. 3B illustrates the corresponding display states.

FIG. 4 is a flowchart depicting a method of controlling thetransmissivity of an embodiment of an AR-HMD device.

DETAILED DESCRIPTION OF EMBODIMENTS

AR systems and devices provide the ability to overlay information on topof the real world seen by the user's natural vision. FIG. 1 depicts ageneric AR head mounted display (HMD) device that can be worn on auser's head (e.g., on a user's face). The AR-HMD device includes one ormore display devices 109 integrated with imaging optics, such as, forexample, focusing and/or collimating lenses or elements that directlight from the one or more display devices 109 towards one or moreoptics disposed in front of one or both of the users' eyes 105. Theoptics disposed in front of one or both of the users' eyes 105 caninclude a beam combiner 107, which can direct light from the one or moredisplay devices towards the user's eyes 105 as well as transmit lightfrom objects in the real-world. The beam combiner 107, in someimplementations, can be configured to provide collimation and may haveoptical power. Such AR-HMD devices that transmit light from thereal-world objects towards the user's eyes can be referred to assee-through AR-HMD devices. The optics disposed in front of one or bothof the users' eyes 105 can be supported by a frame that can be worn onor around the user's head (e.g., face). In various embodiments, theframe supporting the optics (e.g. beam combiner) disposed in front ofone or both of the users' eyes 105 can include straps or ear stems. Theone or more display devices 109 can be configured to receive visualinformation (e.g., text, graphics, video, etc.) that can modify oraugment the physical real-world perceived by the user 101. As discussedabove, examples of such information may include, maps, GPS data, photos.Visual information can be generated by an electronic hardware processingsystem (e.g., a computing device or electronics) that is transmitted tothe AR-HMD device, for example, using wired or wireless technologies. Invarious embodiments, the electronic hardware processing system orprocessing electronics can be integrated with the AR-HMD device. In someembodiments, the electronic hardware processing system or processingelectronics can be located remotely from the AR-HMD device.

In operation, ambient light from the real-world surrounding the user 101is transmitted through the beam combiner 107 and directed towards theuser's eyes 105 thereby allowing the user 101 to see objects in thereal-world. The visual information (e.g., text, video, data, graphics,etc.) generated by the electronic hardware processing system isdisplayed on the one or more display devices 109. Light from the displaydevice 109 is reflected by the beam combiner 107 towards the user's eyes105. Accordingly, the user 101 perceives the generated visualinformation simultaneously with the objects in the real-world as thoughthe generated visual information is overlaid on objects in thereal-world or disposed adjacent to these real-world object and is a partof the real-world. For example, referring to FIG. 1, the user 101perceives the location information 111 which is visual informationgenerated by the electronic hardware processing system or processingelectronics superimposed on or disposed adjacent to a house 103 in thereal-world scene. In this manner, the user's perception of reality ismodified or augmented.

In various embodiments of AR systems, the beam combiner 107 can includeat least one of partially metallized mirrors, dielectric coatings,dichroic coatings and/or interference coatings disposed on atransmissive material, partially transmissive mirrors, waveguide devicesor polarization beam combiners. The display device 109 can comprisebacklit liquid crystal display (LCD) technology such as a reflective ortransmissive LCD display, light emitting diode (LED) based displaydevices, organic LED (OLED) display devices or other types of displays.Accordingly, in various embodiments, the display device 109 can comprisea transmissive display, a reflective display or an emissive display.

AR-HMD devices can provide many benefits in situational awareness whichinvolves obtaining information in real-time about events occurring inthe surrounding environment and using the obtained information tocontrol one's own actions to achieve a desired objective immediately andin the near future. Accordingly, AR-HMD devices can find many uses indefense, homeland security, emergency management and/or rescue andrecovery operations. The light emitted from the one or more displaydevices 109 that includes the generated virtual visual information canleak out of the AR-HMD device worn by the user 101 or be scattered fromthe user's eyes 105 and/or other facial structures and can be seen bypeople or detected by devices in the surrounding environment. This straylight can be disadvantageous when the AR-HMD device is used fornighttime military operations as emitting noticeable amounts of lightfrom the user 101 that can be seen or detected can be counterproductiveto clandestine operations. Accordingly, it can be advantageous to reduceor prevent leakage of the light emitted from the display device into thesurrounding environment.

AR-HMD Device with Increased Light Security

FIG. 2 schematically depicts an embodiment of an AR-HMD device that isconfigured to reduce leakage of light from the display device. TheAR-HMD device comprises an optical shutter 205 that is controlled bysignals from an electronic hardware control system 210 or controlelectronics. The optical shutter 205 is disposed between the beamcombiner 107 and the real world to reduce leakage of stray light fromthe one or more display devices 109. Accordingly, the optical shutter205 can be disposed at the output of the optic of the AR-HMD device. Theoptical shutter 205 can be configured to transition between a firstblocking state in which the optical shutter 205 can substantially blocklight from the one or more display devices 109 that is forward directedtowards the environment after scattering from the user's eye 105 and/orfacial structures of the user 101 and a second transmissive state inwhich the optical shutter 205 can allow ambient light from theenvironment to be transmitted to the user's eye through the beamcombiner 107. The optical shutter 205 can be referred to as being closedwhen configured to be in the first state and referred to as being openwhen configured to be in the second state. Light leakage from the one ormore display devices 109 can be eliminated or substantially reduced whenthe optical shutter 205 is closed and the AR-HMD device is provided witha housing including eyecups and/or baffles or some other configurationfor eliminating or preventing light from leaking around the opticalshutter 205. Accordingly, providing the optical shutter canadvantageously increase light security of AR-HMD devices. The opticalshutter 205 can allow the user 101 to see the ambient environment in theforward direction when the optical shutter 205 is configured to be inthe second state, yet block stray or scattered light from the displaywhen in the first state.

As discussed above, the AR-HMD devices can be configured such that thevisual information generated by the electronic hardware processingsystem can be overlaid on and/or presented adjacent to the view ofobjects in the real-world environment so as to modify and/or augment theview of the real-world environment in real-time. Accordingly, theoptical shutter 205 can be transitioned between the first and the secondstates at rates such that the user 101 can perceive the virtual visualinformation along with the real-world objects without experiencing atime lag. For example, the optical shutter 205 can be transitionedbetween the first and the second states at a rate faster than theunaided human eye can detect. For example, the optical shutter 205 canbe transitioned between the first and the second states at timeintervals that are comparable to or less than the persistence ofvision—which is approximately 1/16 of a second such that the real-worldobjects and the virtual visual information are blended together. Forexample, the optical shutter 205 can be transitioned between the firstand the second states at a time intervals between about 1 microsecondand about 100 milliseconds; between about 10 microseconds and about 70milliseconds; between about 50 microseconds and about 65 milliseconds;between about 75 microseconds and about 50 milliseconds; between about100 microseconds and about 40 milliseconds; between about 200microseconds and about 30 milliseconds; between about 300 microsecondsand about 20 milliseconds; between about 500 microseconds and about 10milliseconds; between about 1 millisecond and about 5 milliseconds; orany values in these ranges/sub-ranges.

When the optical shutter 205 is transitioned between the first and thesecond states at time intervals that are comparable to or less than thepersistence of vision in the period during which the optical shutter 205is referred to as being open, ambient light from objects in thesurrounding environment is transmitted through the beam combiner 107towards the user's eyes 105 and in the period during which the opticalshutter 205 is referred to as being closed, light from the one or moredisplay devices 109 modulated by the virtual visual information thatmodifies and/or augments objects in the real-world environment isreflected by the beam combiner 107 towards the user's eyes 105. Theobjects in the real-world and the virtual visual information areperceived simultaneously by the user 101 due to persistence of vision.Advantageously, in the period during which the optical shutter 205 isconsidered to be closed, most or all of the light from the one or moredisplay devices 109 is prevented from being directed out of the AR-HMDdevice into the surrounding environment thus increasing the lightsecurity of the AR-HMD device. The optical shutter can be considered tobe opaque when it is configured to be in the first blocking state (orclosed state), since the optical shutter 205 prevents light fromentering or exiting the AR-HMD device when configured to be in the firstblocking state. The optical shutter can be considered to be transmissivewhen it is configured to be in the second transmissive state (or openstate), since the optical shutter 205 allows light to enter the AR-HMDdevice when configured to be in the second transmissive state.

In various embodiments, the optical shutter 205 can comprise anopto-mechanical or electro-optical device that can be transitionedbetween the first state and second state by application of an electricalsignal (e.g., an electrical voltage, an electrical charge, etc.). Insome embodiments, the optical shutter 205 can comprise a liquid crystalmodulator that can be transitioned between the first state and secondstate by application of an electrical signal (e.g., an electricalvoltage). In some embodiments, the optical shutter 205 can comprise aTwisted Nematic (TN) liquid crystal element and/or a ferroelectricliquid crystal element. In some embodiments, the optical shutter 205 caninclude an electrochromic device. In other embodiments, the opticalshutter 205 can include other materials and/or devices that are known inthe art. The optical shutter 205 can comprise absorbers to furtherdecrease leakage of forward directed light from the one or more displaydevices 109 in some embodiments.

As discussed above, the transitioning of the optical shutter 205 betweenthe first blocking state and the second transmissive state can becontrolled by signals from the electronic hardware control system orcontrol electronics 210. For example, the electronic hardware controlsystem 210 can be configured to provide electromagnetic signals (e.g.,electrical current, electrical voltage, electrical charge, etc.) to theoptical shutter 205 to switch the optical shutter 205 between the firstblocking state and the second transmissive state. The optical shuttercan be opened and closed at fast rates (e.g., at a rate between about 1microsecond and about 100 milliseconds). The electronic hardware controlsystem 210 can include components (e.g., capacitors, inductors,transistors, diodes, resistors, etc.) with fast frequency response thatcan generate signals with fast rise and fall times. For example, thecomponents of the electronic hardware control system 210 can have timeconstants that can generate signals with rise and fall times of lessthan about 1 microsecond—10 milliseconds or less than about 1microsecond—100 milliseconds. The electronic hardware control system 210can be configured to provide the signals that maintains the opticalshutter 205 in the first state for an interval of time t_(block) andthen switch the optical shutter 205 from the first state to the secondstate and maintain the optical shutter 205 in the second state for aninterval of time t_(transmit) and/or vice-versa. The interval of timet_(block) for which the optical shutter 205 is maintained in the firststate and/or the interval of time t_(transmit) and/or for which theoptical shutter 205 is maintained in the second state can be less thanor equal to persistence of vision. For example, in various embodiments,the interval of time t_(block) for which the optical shutter 205 ismaintained in the first state and/or the interval of time t_(transmit)and/or for which the optical shutter 205 is maintained in the secondstate can be less than or equal to about 1 microsecond and about 100milliseconds; about 10 microseconds and about 70 milliseconds; about 50microseconds and about 65 milliseconds; about 75 microseconds and about50 milliseconds; about 100 microseconds and about 40 milliseconds; about200 microseconds and about 30 milliseconds; about 300 microseconds andabout 20 milliseconds; about 500 microseconds and about 10 milliseconds;about 1 millisecond and about 5 milliseconds; or any values in theseranges/sub-ranges.

FIG. 3A illustrates a graph 302 that shows the variation in the controlvoltage with respect to time provided by an embodiment of the electronichardware control system 210 to an embodiment of an optical shutter 205and the corresponding graph 304 that shows the variation in thetransmissivity of the optical shutter 205. The embodiment of theelectronic hardware control system 210 can be configured to provide ablocking voltage V_(block) and a transmit voltage V_(transmit). Theblocking voltage V_(block) can be lower than the transmit voltageV_(transmit) as illustrated in FIG. 3A. However, in other embodiments,the blocking voltage V_(block) can be greater than the transmit voltageV_(transmit). The blocking voltage V_(block) and/or transmit voltageV_(transmit) can be positive or negative. The blocking voltage V_(block)and the transmit voltage V_(transmit) can have a magnitude in the rangebetween about 1.0 mV and about 10V. Other values, however, are alsopossible. The optical shutter 205 can have a first transmissivity T₁when the blocking voltage V_(block) is provided and have a secondtransmissivity T₂ when the transmit voltage V_(transmit) is provided.The first transmissivity T₁ can be between 0 and about 30%. The secondtransmissivity T₂ can be between about 50% and about 100% in someembodiments. In some embodiments, the second transmissivity T₂ can bebetween about 40% and about 100%

The electronic hardware control system 210 can be configured to providethe blocking voltage V_(block) for a first duration of time t_(block)and the transmit voltage V_(transmit) for a second duration of timet_(transmit). The first and/or the second duration of time t_(block) andt_(transmit) can be between about 1 microsecond and about 100milliseconds. As discussed above, in the first duration of timet_(block) the optical shutter 205 can block greater than 70% of thelight emitted from or reflected by the one or more display devices 109that passes through the beam combiner 107 or is incident on the opticalshutter 205. In some embodiments, the optical shutter 205 may blockgreater than 80% of the light emitted from or reflected by the one ormore display devices 109 that passes through the beam combiner 107 or isincident on the optical shutter 205. The optical shutter 205 may in someimplementations block greater than 90% of the light emitted from orreflected by the one or more display devices 109 that passes through thebeam combiner 107 or is incident on the optical shutter 105. In someimplementations, the optical shutter 105 may block 100% of the lightemitted from or reflected by the one or more display devices 109 thatpasses through the beam combiner 107 or is incident on the opticalshutter 205 but in many cases, leakage may nevertheless exist. Forexample, the shutter may block less than 100% of the light emitted fromor reflected by the one or more display devices 109 that passes throughthe beam combiner 107 or is incident on the optical shutter 205. In someimplementations, the optical shutter 205 may block less than 98% of thelight emitted from or reflected by the one or more display devices 109that passes through the beam combiner 107 or is incident on the opticalshutter 205. Or the optical shutter 205 may block less than 95% of thelight emitted from or reflected by the one or more display devices 109that passes through the beam combiner 107 or is incident on the opticalshutter 205. Any ranges between the values set forth herein arepossible.

The electronic hardware control system or control electronics 210 can beconfigured to switch the transmissivity of the optical shutter 205between the first and the second transmissivities T₁ and T₂ periodicallyas shown in FIG. 3A, however in other implementations, the switchingbetween the transmissivity of the optical shutter 205 between the firstand the second transmissivities T₁ and T₂ need not be periodic. As shownin FIG. 3A, the duty cycle of the electrical signal provided by theelectronic hardware control system 210 need not be 1:1. Rather, as shownin FIG. 3A, the optical shutter 205 may be configured to be maintainedat the second transmissivity T₂ for a longer duration of timet_(transmit) than the duration of time t_(block) for which the opticalshutter 205 is maintained at the first transmissivity T₁. Although, forthe embodiment illustrated in FIG. 3A, t_(transmit) is greater thant_(block), in other embodiments, t_(transmit) can be less than or equalto t_(block). The electronic hardware control system 210 may beconfigured to synchronize the variation in the transmissivity of theoptical shutter 205 with the one or more display devices 109. Forexample, the electronic hardware control system 210 can be configured tomaintain the transmissivity of the optical shutter 205 at the secondtransmissivity T₂ (e.g., in the open state) when the one or more displaydevices 109 are off and maintain the transmissivity of the opticalshutter 205 at the first transmissivity T₁ (e.g., in the closed state)when the one or more display devices 109 are on. Accordingly, theoptical shutter 205 has increased transmissivity (or is open) for theduration of time when the one or more display devices 109 are off (or ina dark or low light output state) and the optical shutter 205 hasdecreased transmissivity (or is closed) for the duration of time whenthe one or more display devices 109 are on (or in a bright or high lightoutput state) such that most of the light from the one or more displaydevices 109 that would otherwise be reach an onlooker, for example, infront of the user 101 when light is emanating from the one or moredisplay devices 109 is blocked. Accordingly, the AR-HMD device discussedabove provides a see-through system with increased light security.

FIG. 3B shows a graph 308 that shows the variation in the state of theone or more display devices 109 corresponding to the variation in thetransmissivity of optical shutter 205. As noted from graph 308, the oneor more display devices 109 are turned on (or in a bright or high lightoutput state) in the time interval t_(block) when the optical shutter205 has reduced transmissivity T₁ and turned off (or in a dark or lowlight output state) in the time interval t_(transmit) when the opticalshutter 205 has increased transmissivity T₂. The electronic hardwarecontrol system 210 can be configured to turn the one or more displaydevices 109 on or off by providing a display voltage equivalent toV_(on) when the control voltage provided to the optical shutter 205 isequal to V_(block) and providing a display voltage equivalent to V_(off)when the control voltage provided to the optical shutter is equal toV_(transmit). Other configurations or arrangement for controlling thedisplay are also possible. The graph 306 shows the variation in thedisplay voltage provided by the electronic hardware control system 210with time. Once again, however, the display may be configureddifferently.

FIG. 4 is a flowchart depicting a method 400 of controlling thetransmissivity of an embodiment of an AR-HMD device comprising anoptical shutter, such as, for example, the optical shutter 205 depictedin FIG. 2. The method 400 may be implemented by an electronic processor(e.g., electronic processing systems or processing electronics of theelectronic hardware control system or control electronics 210). Themethod 400 includes providing a voltage that switches off the displaydevice and providing a voltage that switches the optical shutter to astate of increased transmittance as shown in block 405 to allow ambientlight to enter the AR-HMD device. For example, the electronic processorcan be configured to provide an electrical voltage equal to V_(off) thatswitches off (or to a dark or low light output state) the one or moredisplay devices and provide a voltage V_(transmit) that transitions theshutter to a state of increased transmittance (e.g., having atransmittance T2) such that the optical shutter is in an open ortransmissive state. The method 400 further include providing a voltagethat switches on (or to a bright or high light output state) the displaydevice and providing a voltage that switches the optical shutter to astate of decreased transmittance as shown in block 410 to block orprevent leakage of light from the display device. For example, theelectronic processor can be configured to provide an electrical voltageequal to V_(block) that transitions the shutter to a state of decreasedtransmittance (e.g., having a transmittance T₁) such that the opticalshutter is in a blocked or closed state. In this manner, thetransmissivity of the optical shutter can be synchronized with thedisplay device.

Although, various embodiments of the optical systems and methods aredescribed with reference to an augmented reality head mounted displaydevice, they can be used in other application as well including but notlimited to a tank sight or a gun sight. Various embodiments of theoptical systems and methods described herein can be used for defenseapplications and/or homeland security applications.

Each of the processes, methods, and algorithms described herein and/ordepicted in the attached figures may be embodied in, and fully orpartially automated by, code modules executed by one or more physicalcomputing systems, hardware computer processors, application-specificcircuitry, field programmable gate arrays (FPGAs) and/or electronichardware configured to execute specific and particular computerinstructions. For example, computing systems can include general purposecomputers programmed with specific computer instructions or specialpurpose computers, special purpose circuitry, and so forth. A codemodule may be compiled and linked into an executable program, installedin a dynamic link library, or may be written in an interpretedprogramming language. In some implementations, particular operations andmethods may be performed by circuitry that is specific to a givenfunction.

Further, certain implementations of the functionality of the presentdisclosure are sufficiently mathematically, computationally, ortechnically complex that application-specific hardware or one or morephysical computing devices (utilizing appropriate specialized executableinstructions) may be necessary to perform the functionality, forexample, due to the volume or complexity of the calculations involved orto provide results substantially in real-time. For example, a video mayinclude many frames, with each frame having millions of pixels, andspecifically programmed computer hardware is necessary to process thevideo data to provide a desired image processing task or application ina commercially reasonable amount of time, such as for example of otherorder of a few hundred microseconds to a few milliseconds.

Code modules or any type of data may be stored on any type ofnon-transitory computer-readable medium, such as physical computerstorage including hard drives, solid state memory, random access memory(RAM), read only memory (ROM), optical disc, volatile or non-volatilestorage, combinations of the same and/or the like. The methods andmodules (or data) may also be transmitted as generated data signals(e.g., as part of a carrier wave or other analog or digital propagatedsignal) on a variety of computer-readable transmission mediums,including wireless-based and wired/cable-based mediums, and may take avariety of forms (e.g., as part of a single or multiplexed analogsignal, or as multiple discrete digital packets or frames). The resultsof the disclosed processes or process steps may be stored, persistentlyor otherwise, in any type of non-transitory, tangible computer storageor may be communicated via a computer-readable transmission medium.

Any processes, blocks, states, steps, or functionalities in flowdiagrams described herein and/or depicted in the attached figures shouldbe understood as potentially representing code modules, segments, orportions of code which include one or more executable instructions forimplementing specific functions (e.g., logical or arithmetical) or stepsin the process. The various processes, blocks, states, steps, orfunctionalities can be combined, rearranged, added to, deleted from,modified, or otherwise changed from the illustrative examples providedherein. In some embodiments, additional or different computing systemsor code modules may perform some or all of the functionalities describedherein. The methods and processes described herein are also not limitedto any particular sequence, and the blocks, steps, or states relatingthereto can be performed in other sequences that are appropriate, forexample, in serial, in parallel, or in some other manner. Tasks orevents may be added to or removed from the disclosed exampleembodiments. Moreover, the separation of various system components inthe implementations described herein is for illustrative purposes andshould not be understood as requiring such separation in allimplementations. It should be understood that the described programcomponents, methods, and systems can generally be integrated together ina single computer product or packaged into multiple computer products.Many implementation variations are possible.

The processes, methods, and systems may be implemented in a network (ordistributed) computing environment. Network environments includeenterprise-wide computer networks, intranets, local area networks (LAN),wide area networks (WAN), personal area networks (PAN), cloud computingnetworks, crowd-sourced computing networks, the Internet, and the WorldWide Web. The network may be a wired or a wireless network or any othertype of communication network.

The systems and methods of the disclosure each have several innovativeaspects, no single one of which is solely responsible or required forthe desirable attributes disclosed herein. The various features andprocesses described above may be used independently of one another, ormay be combined in various ways. All possible combinations andsubcombinations are intended to fall within the scope of thisdisclosure. Various modifications to the implementations described inthis disclosure may be readily apparent to those skilled in the art, andthe generic principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. Thus, the claims are not intended to be limited to theimplementations shown herein, but are to be accorded the widest scopeconsistent with this disclosure, the principles and the novel featuresdisclosed herein.

Certain features that are described in this specification in the contextof separate implementations also can be implemented in combination in asingle implementation. Conversely, various features that are describedin the context of a single implementation also can be implemented inmultiple implementations separately or in any suitable subcombination.Moreover, although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination. No single feature orgroup of features is necessary or indispensable to each and everyembodiment.

Conditional language used herein, such as, among others, “can,” “could,”“might,” “may,” “e.g.,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements and/orsteps. Thus, such conditional language is not generally intended toimply that features, elements and/or steps are in any way required forone or more embodiments or that one or more embodiments necessarilyinclude logic for deciding, with or without author input or prompting,whether these features, elements and/or steps are included or are to beperformed in any particular embodiment. The terms “comprising,”“including,” “having,” and the like are synonymous and are usedinclusively, in an open-ended fashion, and do not exclude additionalelements, features, acts, operations, and so forth. Also, the term “or”is used in its inclusive sense (and not in its exclusive sense) so thatwhen used, for example, to connect a list of elements, the term “or”means one, some, or all of the elements in the list. In addition, thearticles “a,” “an,” and “the” as used in this application and theappended claims are to be construed to mean “one or more” or “at leastone” unless specified otherwise.

As used herein, a phrase referring to “at least one of a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: A, B, or C” is intended to cover: A, B, C,A and B, A and C, B and C, and A, B, and C. Conjunctive language such asthe phrase “at least one of X, Y and Z,” unless specifically statedotherwise, is otherwise understood with the context as used in generalto convey that an item, term, etc. may be at least one of X, Y or Z.Thus, such conjunctive language is not generally intended to imply thatcertain embodiments require at least one of X, at least one of Y and atleast one of Z to each be present.

Similarly, while operations may be depicted in the drawings in aparticular order, it is to be recognized that such operations need notbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Further, the drawings may schematically depict one more exampleprocesses in the form of a flowchart. However, other operations that arenot depicted can be incorporated in the example methods and processesthat are schematically illustrated. For example, one or more additionaloperations can be performed before, after, simultaneously, or betweenany of the illustrated operations. Additionally, the operations may berearranged or reordered in other implementations. In certaincircumstances, multitasking and parallel processing may be advantageous.Moreover, the separation of various system components in theimplementations described above should not be understood as requiringsuch separation in all implementations, and it should be understood thatthe described program components and systems can generally be integratedtogether in a single software product or packaged into multiple softwareproducts. Additionally, other implementations are within the scope ofthe following claims. In some cases, the actions recited in the claimscan be performed in a different order and still achieve desirableresults.

1. An optical system comprising: a display device having a first brightdisplay state when the display device emits light and a second darkdisplay state when the display device emits a reduced amount of light; abeam combiner; and a shutter having a first blocking shutter state inwhich the shutter blocks light passing through the beam combiner andincident on the shutter and a second transmissive shutter state in whichthe shutter transmits light so that light can pass through the beamcombiner, the shutter configured to be controlled by a control system,such that the shutter is in the first blocking shutter state when thedisplay device emits light and the shutter is in the second transmissiveshutter state when the amount of light emitted from the display deviceis reduced. 2.-30. (canceled)